Science Of Piezoelectricity: Generate Electricity While You Groove On The Dance Floor

Yes, a piezoelectric dance floor really can generate electricity while you groove. Piezoelectric tiles turn the pressure of each footstep into a small electric charge. The catch is that the output is tiny, only a few watts per step, so it takes a packed, moving crowd to help power a club's lights and sound.

Wouldn’t it be great if we could harness the energy from our steps while walking or running? What if we could charge our smartphones by dancing on some energy-capturing floor in a club? That really would be amazing, but it seems pretty far-fetched, right?

When you think about it, due to the spread of technology and the constant demand for electricity all over the world, this method of harnessing energy would become extremely useful to meet these energy requirements…

What if I told you that similar methods of electricity-harnessing are already being utilized in some places around the world?

Piezoelectricity

Energy generation using this method is based on the concept of piezoelectricity. Piezoelectricity is the electric charge that certain solid materials build up when you squeeze, bend or otherwise stress them (like the pressure of walking, running or dancing). The materials that do this best are crystals and ceramics, but it also shows up in some biological tissues, such as bone, where it is thought to help the body sense load and remodel itself.

The effect was discovered back in 1880 by the French brothers Pierre and Jacques Curie, who found that squeezing crystals like quartz and Rochelle salt produced a measurable voltage. This is the direct piezoelectric effect: mechanical stress in, electric charge out, which is exactly what a dance floor relies on. Run it in reverse (apply a voltage and the crystal physically deforms) and you get the converse effect, the trick behind ultrasound probes and the tiny buzzers in many of your gadgets.

How Does It Generate Electricity?

When pressure is applied to a piezoelectric material, it briefly pushes opposite charges to opposite faces; a negative charge gathers on the stretched side and a positive charge on the compressed side. Let’s see how this works when mechanical movement (like walking or dancing) is involved. If you happen to dance on a floor that is equipped with piezoelectric technology, as soon as your feet hit the floor, a certain amount of pressure is applied. This pressure is captured by the floor’s piezo elements and is converted into a brief electrical charge. The materials doing the heavy lifting are usually crystals or ceramics, the classics being quartz and Rochelle salt, while modern tiles lean on a man-made ceramic called PZT (lead zirconate titanate) or a flexible plastic called PVDF. That charge is then collected and stored so it can be used as a power source.

The ‘Crowd’ Key

In order to harness viable energy using this method, it is crucial that there be a large number of people on the floor who are in a state of movement at the same time. In other words, you should be looking for a crowd, like the ones you see at busy railway stations and shopping malls. You need a crowd because a single footstep just doesn’t provide enough pressure. A single step on a piezoelectric tile yields only a few watts, often less, which barely lights an LED. But when thousands of people are walking, running or dancing at the same time, those tiny contributions add up. At a trial installation in a Tokyo train station, for instance, the energy gathered from commuters over a day was enough to keep a 100-watt bulb glowing for over an hour. The takeaway is simple: the bigger and more energetic the crowd, the more power you get, so jogging or dancing beats a gentle stroll every time.

Applications

A number of places and companies have already tried to install piezoelectric floors to harness energy in this way. A much-publicized example was Club Surya in London, an eco-club whose owner set out to run the place on greener power, with a piezoelectric dance floor as the centerpiece alongside solar panels and a wind turbine. The often-quoted line that a busy night could supply around 60% of the club’s energy was the owner’s own projection rather than a verified, metered result, so treat it as the optimistic end of what these floors might do.

An even better-documented case was Club Watt in Rotterdam, which opened a "sustainable dance floor" built by the Dutch company Energy Floors. Each floor module produces only about 25 to 35 watts when people really get moving on it, and the floor was credited with helping the club trim roughly 30% off the power it needed. That is a meaningful dent, but notice the scale: we are talking watts, not kilowatts, even with a full house jumping around.

It is worth remembering that piezoelectricity does far more useful work away from the dance floor. The same effect keeps time in a quartz wristwatch, fires the spark in a gas-lighter or barbecue igniter when you click it, sends and receives the pulses inside medical ultrasound scanners, and bounces sound off the seabed in sonar. These jobs play to its real strength: precise, tiny, repeatable signals, rather than bulk power generation.

So why aren’t our streets and stations already paved with these tiles? There are certain issues to consider. The cost of installing the necessary equipment is quite high, and the amount of power produced in a day is modest at best. Even so, who knows… in the coming years, we may have better and cheaper materials to make this method of harnessing energy worthwhile.

Finally, you’ll have a ‘green’ reason to saunter through shopping malls for as long as you want!